PG(1) User Commands PG(1)


pg - files perusal filter for CRTs


pg [-number] [-p string] [-cefnrs] [+ linenumber]
[+/ pattern /] [filename]...


The pg command is a filter that allows the examination of filenames one
screenful at a time on a CRT. If the user types a RETURN, another page is
displayed; other possibilities are listed below.

This command is different from previous paginators in that it allows you
to back up and review something that has already passed. The method for
doing this is explained below.

To determine terminal attributes, pg scans the terminfo(5) data base for
the terminal type specified by the environment variable TERM. If TERM is
not defined, the terminal type dumb is assumed.


An integer specifying the size (in lines) of the window
that pg is to use instead of the default. (On a terminal
containing 24 lines, the default window size is 23).

pg uses string as the prompt. If the prompt string
contains a %d, the first occurrence of %d in the prompt
will be replaced by the current page number when the
prompt is issued. The default prompt string is ``:''.

Home the cursor and clear the screen before displaying
each page. This option is ignored if clear_screen is not
defined for this terminal type in the terminfo(5) data

pg does not pause at the end of each file.

Normally, pg splits lines longer than the screen width,
but some sequences of characters in the text being
displayed (for instance, escape sequences for underlining)
generate undesirable results. The -f option inhibits pg
from splitting lines.

Normally, commands must be terminated by a <newline>
character. This option causes an automatic end of command
as soon as a command letter is entered.

Restricted mode. The shell escape is disallowed. pg prints
an error message but does not exit.

pg prints all messages and prompts in the standard output
mode (usually inverse video).

Start up at linenumber.

Start up at the first line containing the regular
expression pattern.


The following operands are supported:

A path name of a text file to be displayed. If no filename is
given, or if it is -, the standard input is read.



The responses that may be typed when pg pauses can be divided into three
categories: those causing further perusal, those that search, and those
that modify the perusal environment.

Commands that cause further perusal normally take a preceding address, an
optionally signed number indicating the point from which further text
should be displayed. This address is interpreted in either pages or lines
depending on the command. A signed address specifies a point relative to
the current page or line, and an unsigned address specifies an address
relative to the beginning of the file. Each command has a default address
that is used if none is provided.

The perusal commands and their defaults are as follows:

(+1)<newline> or <blank>
This causes one page to be displayed. The
address is specified in pages.

(+1) l
With a relative address this causes pg to
simulate scrolling the screen, forward or
backward, the number of lines specified. With
an absolute address this command prints a
screenful beginning at the specified line.

(+1) d or ^D
Simulates scrolling half a screen forward or

Skip i screens of text.

Same as <newline> except that i, if present,
becomes the new default number of lines per

The following perusal commands take no address.

. or ^L
Typing a single period causes the current page of text to be

Displays the last full window in the file. Use with caution
when the input is a pipe.

The following commands are available for searching for text patterns in
the text. The regular expressions are described on the regex(7) manual
page. They must always be terminated by a <newline>, even if the -n
option is specified.

Search forward for the ith (default i=1) occurrence of
pattern. Searching begins immediately after the current
page and continues to the end of the current file, without


Search backwards for the ith (default i=1) occurrence of
pattern. Searching begins immediately before the current
page and continues to the beginning of the current file,
without wrap-around. The ^ notation is useful for Adds 100
terminals which will not properly handle the ?.

After searching, pg will normally display the line found at the top of
the screen. This can be modified by appending m or b to the search
command to leave the line found in the middle or at the bottom of the
window from now on. The suffix t can be used to restore the original

The user of pg can modify the environment of perusal with the following

Begin perusing the ith next file in the command line. The i
is an unsigned number, default value is 1.

Begin perusing the ith previous file in the command line. i
is an unsigned number, default is 1.

Display another window of text. If i is present, set the
window size to i.

s filename
Save the input in the named file. Only the current file
being perused is saved. The white space between the s and
filename is optional. This command must always be
terminated by a <newline>, even if the -n option is

Help by displaying an abbreviated summary of available

q or Q
Quit pg.

Command is passed to the shell, whose name is taken from
the SHELL environment variable. If this is not available,
the default shell is used. This command must always be
terminated by a <newline>, even if the -n option is

At any time when output is being sent to the terminal, the user can hit
the quit key (normally CTRL-\) or the interrupt (break) key. This causes
pg to stop sending output, and display the prompt. The user may then
enter one of the above commands in the normal manner. Unfortunately, some
output is lost when this is done, because any characters waiting in the
terminal's output queue are flushed when the quit signal occurs.

If the standard output is not a terminal, then pg acts just like cat(1),
except that a header is printed before each file (if there is more than

Large File Behavior

See largefile(7) for the description of the behavior of pg when
encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).


Example 1: An example of the pg command.

The following command line uses pg to read the system news:

example% news | pg -p "(Page %d):"


See environ(7) for descriptions of the following environment variables
that affect the execution of pg: LC_CTYPE, LC_MESSAGES, and NLSPATH.

The following environment variables affect the execution of pg:

Determine the horizontal screen size. If unset or NULL, use
the value of TERM, the window size, baud rate, or some
combination of these, to indicate the terminal type for the
screen size calculation.

Determine the number of lines to be displayed on the screen.
If unset or NULL, use the value of TERM, the window size, baud
rate, or some combination of these, to indicate the terminal
type for the screen size calculation.

Determine the name of the command interpreter executed for a

Determine terminal attributes. Optionally attempt to search a
system-dependent database, keyed on the value of the TERM
environment variable. If no information is available, a
terminal incapable of cursor-addressable movement is assumed.


The following exit values are returned:

Successful completion.

An error occurred.



temporary file when input is from a pipe


terminal information database


cat(1), grep(1), more(1), terminfo(5), attributes(7), environ(7),
largefile(7), regex(7)


While waiting for terminal input, pg responds to BREAK, CTRL-C, and
CTRL-\ by terminating execution. Between prompts, however, these signals
interrupt pg's current task and place the user in prompt mode. These
should be used with caution when input is being read from a pipe, since
an interrupt is likely to terminate the other commands in the pipeline.

The terminal /, ^, or ? may be omitted from the searching commands.

If terminal tabs are not set every eight positions, undesirable results
may occur.

When using pg as a filter with another command that changes the terminal
I/O options, terminal settings may not be restored correctly.

February 25, 1996 PG(1)